Biology Reference
In-Depth Information
Fig. 3.
(
a-c
) Herpes Simplex Virus-1 (HSV-1). (a) HSV-1 capsid with hex-
ons and pentons (circles) capsomeres constituting the icosahedral symmetry.
(
b
) High-resolution image of an HSV-1 capsid showing small protein com-
plexes known as triplexes between three (white arrows) as well as two (black
arrows) capsomeres. EM image reconstruction demonstrated these units only
present in the former location. (
c
) HSV-1 capsid as seen by EM. (Reprinted
from http://www.uct.ac.za/depts/mmi/stannard/linda.html. Copyright
Linda M Stannard, 1995) (
d-e
)
Paramecium bursaria
chlorella virus type 1
(PBCV-1). (
d
) PBCV-1 capsids display a honeycomb appearance. (
e
) At high
resolution, the triangular nature of the trimeric coat protein is seen. Note the
hole in the center formed by the loss of one trimer. (
f
) The pentameric
arrangement of proteins about the five-fold vertices, with a unique and dif-
ferent protein seen exactly on the vertex.
HSV-1 capsids demonstrate that the AFM technique provides resolu-
tion comparable to conventional EM techniques (Fig. 3c). It must be
emphasized that the HSV-1 virions were not highly purified; never-
theless, effective analysis of virion components was possible. This
demonstrates that AFM visualization can be applied effectively to rel-
atively crude virus preparations.
